[deliverable/linux.git] / arch / x86 / Kconfig.debug

menu "Kernel hacking"

config TRACE_IRQFLAGS_SUPPORT
	def_bool y

source "lib/Kconfig.debug"

config EARLY_PRINTK
	bool "Early printk" if EMBEDDED
	default y
	help
	  Write kernel log output directly into the VGA buffer or to a serial
	  port.

	  This is useful for kernel debugging when your machine crashes very
	  early before the console code is initialized. For normal operation
	  it is not recommended because it looks ugly and doesn't cooperate
	  with klogd/syslogd or the X server. You should normally N here,
	  unless you want to debug such a crash.

config DEBUG_STACKOVERFLOW
	bool "Check for stack overflows"
	depends on DEBUG_KERNEL
	help
	  This option will cause messages to be printed if free stack space
	  drops below a certain limit.

config DEBUG_STACK_USAGE
	bool "Stack utilization instrumentation"
	depends on DEBUG_KERNEL
	help
	  Enables the display of the minimum amount of free stack which each
	  task has ever had available in the sysrq-T and sysrq-P debug output.

	  This option will slow down process creation somewhat.

comment "Page alloc debug is incompatible with Software Suspend on i386"
	depends on DEBUG_KERNEL && HIBERNATION
	depends on X86_32

config DEBUG_PAGEALLOC
	bool "Debug page memory allocations"
	depends on DEBUG_KERNEL && X86_32
	help
	  Unmap pages from the kernel linear mapping after free_pages().
	  This results in a large slowdown, but helps to find certain types
	  of memory corruptions.

config DEBUG_PER_CPU_MAPS
	bool "Debug access to per_cpu maps"
	depends on DEBUG_KERNEL
	depends on X86_64_SMP
	default n
	help
	  Say Y to verify that the per_cpu map being accessed has
	  been setup.  Adds a fair amount of code to kernel memory
	  and decreases performance.

	  Say N if unsure.

config DEBUG_RODATA
	bool "Write protect kernel read-only data structures"
	default y
	depends on DEBUG_KERNEL
	help
	  Mark the kernel read-only data as write-protected in the pagetables,
	  in order to catch accidental (and incorrect) writes to such const
	  data. This is recommended so that we can catch kernel bugs sooner.
	  If in doubt, say "Y".

config DEBUG_RODATA_TEST
	bool "Testcase for the DEBUG_RODATA feature"
	depends on DEBUG_RODATA
	help
	  This option enables a testcase for the DEBUG_RODATA
	  feature as well as for the change_page_attr() infrastructure.
	  If in doubt, say "N"

config DEBUG_NX_TEST
	tristate "Testcase for the NX non-executable stack feature"
	depends on DEBUG_KERNEL && m
	help
	  This option enables a testcase for the CPU NX capability
	  and the software setup of this feature.
	  If in doubt, say "N"

config 4KSTACKS
	bool "Use 4Kb for kernel stacks instead of 8Kb"
	depends on DEBUG_KERNEL
	depends on X86_32
	help
	  If you say Y here the kernel will use a 4Kb stacksize for the
	  kernel stack attached to each process/thread. This facilitates
	  running more threads on a system and also reduces the pressure
	  on the VM subsystem for higher order allocations. This option
	  will also use IRQ stacks to compensate for the reduced stackspace.

config X86_FIND_SMP_CONFIG
	def_bool y
	depends on X86_LOCAL_APIC || X86_VOYAGER
	depends on X86_32

config X86_MPPARSE
	def_bool y
	depends on (X86_32 && (X86_LOCAL_APIC && !X86_VISWS)) || X86_64

config DOUBLEFAULT
	default y
	bool "Enable doublefault exception handler" if EMBEDDED
	depends on X86_32
	help
	  This option allows trapping of rare doublefault exceptions that
	  would otherwise cause a system to silently reboot. Disabling this
	  option saves about 4k and might cause you much additional grey
	  hair.

config IOMMU_DEBUG
	bool "Enable IOMMU debugging"
	depends on GART_IOMMU && DEBUG_KERNEL
	depends on X86_64
	help
	  Force the IOMMU to on even when you have less than 4GB of
	  memory and add debugging code. On overflow always panic. And
	  allow to enable IOMMU leak tracing. Can be disabled at boot
	  time with iommu=noforce. This will also enable scatter gather
	  list merging.  Currently not recommended for production
	  code. When you use it make sure you have a big enough
	  IOMMU/AGP aperture.  Most of the options enabled by this can
	  be set more finegrained using the iommu= command line
	  options. See Documentation/x86_64/boot-options.txt for more
	  details.

config IOMMU_LEAK
	bool "IOMMU leak tracing"
	depends on DEBUG_KERNEL
	depends on IOMMU_DEBUG
	help
	  Add a simple leak tracer to the IOMMU code. This is useful when you
	  are debugging a buggy device driver that leaks IOMMU mappings.

#
# IO delay types:
#

config IO_DELAY_TYPE_0X80
	int
	default "0"

config IO_DELAY_TYPE_0XED
	int
	default "1"

config IO_DELAY_TYPE_UDELAY
	int
	default "2"

config IO_DELAY_TYPE_NONE
	int
	default "3"

choice
	prompt "IO delay type"
	default IO_DELAY_0XED

config IO_DELAY_0X80
	bool "port 0x80 based port-IO delay [recommended]"
	help
	  This is the traditional Linux IO delay used for in/out_p.
	  It is the most tested hence safest selection here.

config IO_DELAY_0XED
	bool "port 0xed based port-IO delay"
	help
	  Use port 0xed as the IO delay. This frees up port 0x80 which is
	  often used as a hardware-debug port.

config IO_DELAY_UDELAY
	bool "udelay based port-IO delay"
	help
	  Use udelay(2) as the IO delay method. This provides the delay
	  while not having any side-effect on the IO port space.

config IO_DELAY_NONE
	bool "no port-IO delay"
	help
	  No port-IO delay. Will break on old boxes that require port-IO
	  delay for certain operations. Should work on most new machines.

endchoice

if IO_DELAY_0X80
config DEFAULT_IO_DELAY_TYPE
	int
	default IO_DELAY_TYPE_0X80
endif

if IO_DELAY_0XED
config DEFAULT_IO_DELAY_TYPE
	int
	default IO_DELAY_TYPE_0XED
endif

if IO_DELAY_UDELAY
config DEFAULT_IO_DELAY_TYPE
	int
	default IO_DELAY_TYPE_UDELAY
endif

if IO_DELAY_NONE
config DEFAULT_IO_DELAY_TYPE
	int
	default IO_DELAY_TYPE_NONE
endif

config DEBUG_BOOT_PARAMS
	bool "Debug boot parameters"
	depends on DEBUG_KERNEL
	depends on DEBUG_FS
	help
	  This option will cause struct boot_params to be exported via debugfs.

config CPA_DEBUG
	bool "CPA self test code"
	depends on DEBUG_KERNEL
	help
	  Do change_page_attr self tests at boot.

endmenu
Commit	Line	Data
1da177e4 LT	1	menu "Kernel hacking"
1da177e4 LT	2
55f327fa	3	config TRACE_IRQFLAGS_SUPPORT
d013a27c	4	def_bool y
55f327fa	5
1da177e4 LT	6	source "lib/Kconfig.debug"
	7
	8	config EARLY_PRINTK
076f9776	9	bool "Early printk" if EMBEDDED
1da177e4 LT	10	default y
	11	help
	12	Write kernel log output directly into the VGA buffer or to a serial
	13	port.
	14
	15	This is useful for kernel debugging when your machine crashes very
	16	early before the console code is initialized. For normal operation
	17	it is not recommended because it looks ugly and doesn't cooperate
	18	with klogd/syslogd or the X server. You should normally N here,
	19	unless you want to debug such a crash.
	20
	21	config DEBUG_STACKOVERFLOW
	22	bool "Check for stack overflows"
	23	depends on DEBUG_KERNEL
dab175f3 AB	24	help
	25	This option will cause messages to be printed if free stack space
	26	drops below a certain limit.
1da177e4	27
1da177e4 LT	28	config DEBUG_STACK_USAGE
	29	bool "Stack utilization instrumentation"
	30	depends on DEBUG_KERNEL
	31	help
	32	Enables the display of the minimum amount of free stack which each
	33	task has ever had available in the sysrq-T and sysrq-P debug output.
	34
	35	This option will slow down process creation somewhat.
	36
	37	comment "Page alloc debug is incompatible with Software Suspend on i386"
b0cb1a19	38	depends on DEBUG_KERNEL && HIBERNATION
d013a27c	39	depends on X86_32
1da177e4 LT	40
1da177e4 LT	41	config DEBUG_PAGEALLOC
4a2f0acf	42	bool "Debug page memory allocations"
86f03989	43	depends on DEBUG_KERNEL && X86_32
1da177e4 LT	44	help
	45	Unmap pages from the kernel linear mapping after free_pages().
	46	This results in a large slowdown, but helps to find certain types
	47	of memory corruptions.
	48
c49a4955	49	config DEBUG_PER_CPU_MAPS
	50	bool "Debug access to per_cpu maps"
	51	depends on DEBUG_KERNEL
	52	depends on X86_64_SMP
	53	default n
	54	help
	55	Say Y to verify that the per_cpu map being accessed has
	56	been setup. Adds a fair amount of code to kernel memory
	57	and decreases performance.
	58
	59	Say N if unsure.
	60
63aaf308 AV	61	config DEBUG_RODATA
63aaf308 AV	62	bool "Write protect kernel read-only data structures"
11201e60	63	default y
63aaf308 AV	64	depends on DEBUG_KERNEL
	65	help
	66	Mark the kernel read-only data as write-protected in the pagetables,
	67	in order to catch accidental (and incorrect) writes to such const
11201e60 IM	68	data. This is recommended so that we can catch kernel bugs sooner.
11201e60 IM	69	If in doubt, say "Y".
63aaf308	70
aba8391f IM	71	config DEBUG_RODATA_TEST
	72	bool "Testcase for the DEBUG_RODATA feature"
	73	depends on DEBUG_RODATA
	74	help
	75	This option enables a testcase for the DEBUG_RODATA
	76	feature as well as for the change_page_attr() infrastructure.
	77	If in doubt, say "N"
	78
	79	config DEBUG_NX_TEST
	80	tristate "Testcase for the NX non-executable stack feature"
	81	depends on DEBUG_KERNEL && m
	82	help
	83	This option enables a testcase for the CPU NX capability
	84	and the software setup of this feature.
	85	If in doubt, say "N"
	86
1da177e4 LT	87	config 4KSTACKS
	88	bool "Use 4Kb for kernel stacks instead of 8Kb"
	89	depends on DEBUG_KERNEL
d013a27c	90	depends on X86_32
1da177e4 LT	91	help
	92	If you say Y here the kernel will use a 4Kb stacksize for the
	93	kernel stack attached to each process/thread. This facilitates
	94	running more threads on a system and also reduces the pressure
	95	on the VM subsystem for higher order allocations. This option
	96	will also use IRQ stacks to compensate for the reduced stackspace.
	97
	98	config X86_FIND_SMP_CONFIG
d013a27c	99	def_bool y
1da177e4	100	depends on X86_LOCAL_APIC \|\| X86_VOYAGER
d013a27c	101	depends on X86_32
1da177e4 LT	102
1da177e4 LT	103	config X86_MPPARSE
d013a27c	104	def_bool y
6b0c3d44	105	depends on (X86_32 && (X86_LOCAL_APIC && !X86_VISWS)) \|\| X86_64
1da177e4	106
102e41fd AK	107	config DOUBLEFAULT
	108	default y
	109	bool "Enable doublefault exception handler" if EMBEDDED
d013a27c RD	110	depends on X86_32
	111	help
	112	This option allows trapping of rare doublefault exceptions that
	113	would otherwise cause a system to silently reboot. Disabling this
	114	option saves about 4k and might cause you much additional grey
	115	hair.
	116
	117	config IOMMU_DEBUG
	118	bool "Enable IOMMU debugging"
966396d3	119	depends on GART_IOMMU && DEBUG_KERNEL
d013a27c	120	depends on X86_64
102e41fd	121	help
d013a27c RD	122	Force the IOMMU to on even when you have less than 4GB of
	123	memory and add debugging code. On overflow always panic. And
	124	allow to enable IOMMU leak tracing. Can be disabled at boot
	125	time with iommu=noforce. This will also enable scatter gather
	126	list merging. Currently not recommended for production
	127	code. When you use it make sure you have a big enough
	128	IOMMU/AGP aperture. Most of the options enabled by this can
	129	be set more finegrained using the iommu= command line
	130	options. See Documentation/x86_64/boot-options.txt for more
	131	details.
	132
	133	config IOMMU_LEAK
	134	bool "IOMMU leak tracing"
	135	depends on DEBUG_KERNEL
	136	depends on IOMMU_DEBUG
	137	help
	138	Add a simple leak tracer to the IOMMU code. This is useful when you
	139	are debugging a buggy device driver that leaks IOMMU mappings.
	140
6e7c4025 IM	141	#
	142	# IO delay types:
	143	#
	144
	145	config IO_DELAY_TYPE_0X80
	146	int
	147	default "0"
	148
	149	config IO_DELAY_TYPE_0XED
	150	int
	151	default "1"
	152
	153	config IO_DELAY_TYPE_UDELAY
	154	int
	155	default "2"
	156
	157	config IO_DELAY_TYPE_NONE
	158	int
	159	default "3"
	160
	161	choice
	162	prompt "IO delay type"
d0049e71	163	default IO_DELAY_0XED
6e7c4025 IM	164
	165	config IO_DELAY_0X80
	166	bool "port 0x80 based port-IO delay [recommended]"
	167	help
	168	This is the traditional Linux IO delay used for in/out_p.
	169	It is the most tested hence safest selection here.
	170
	171	config IO_DELAY_0XED
	172	bool "port 0xed based port-IO delay"
	173	help
	174	Use port 0xed as the IO delay. This frees up port 0x80 which is
	175	often used as a hardware-debug port.
	176
	177	config IO_DELAY_UDELAY
	178	bool "udelay based port-IO delay"
	179	help
	180	Use udelay(2) as the IO delay method. This provides the delay
	181	while not having any side-effect on the IO port space.
	182
	183	config IO_DELAY_NONE
	184	bool "no port-IO delay"
b02aae9c	185	help
6e7c4025 IM	186	No port-IO delay. Will break on old boxes that require port-IO
	187	delay for certain operations. Should work on most new machines.
	188
	189	endchoice
	190
	191	if IO_DELAY_0X80
	192	config DEFAULT_IO_DELAY_TYPE
	193	int
	194	default IO_DELAY_TYPE_0X80
	195	endif
	196
	197	if IO_DELAY_0XED
	198	config DEFAULT_IO_DELAY_TYPE
	199	int
	200	default IO_DELAY_TYPE_0XED
	201	endif
	202
	203	if IO_DELAY_UDELAY
	204	config DEFAULT_IO_DELAY_TYPE
	205	int
	206	default IO_DELAY_TYPE_UDELAY
	207	endif
	208
	209	if IO_DELAY_NONE
	210	config DEFAULT_IO_DELAY_TYPE
	211	int
	212	default IO_DELAY_TYPE_NONE
	213	endif
b02aae9c	214
6d7d7433 HY	215	config DEBUG_BOOT_PARAMS
	216	bool "Debug boot parameters"
	217	depends on DEBUG_KERNEL
	218	depends on DEBUG_FS
	219	help
	220	This option will cause struct boot_params to be exported via debugfs.
	221
0c42f392 AK	222	config CPA_DEBUG
0c42f392 AK	223	bool "CPA self test code"
f316fe68	224	depends on DEBUG_KERNEL
0c42f392 AK	225	help
	226	Do change_page_attr self tests at boot.
	227
1da177e4	228	endmenu